... and stable ingredients, perfect furface quality, high precision dimension. Boiler Seamless steel Pipe Standards and Grades:GB5310, GB3087, 10#, 20#, 20G, 20MnG ... / 22/ 23/ 24/ 25/ 26)JIS G3462 Alloy Steel for Boiler and Heat Exchanger Tubes (STBA12/ 13/ 20/ 22/23)JIS ... , Mechanical properties, Chemical compositions: Refer to ASTM A355, EN10216 or as per clients' requirements HIGH-PRESSURE BOILER PIPE